JP2015199102A - Press-forming device and press-forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press-forming device capable of preventing a line displacement in press working.SOLUTION: A press-forming device includes a punch 13 having a punch press surface 13a provided with ridge lines 13C, 13S thereon, the punch press surface 13a having suction ports 16 formed inside at least the ridge lines 13C, 13S, an upper die to sandwich and press a metal plate together with the punch 13, and a suction device 18 to communicate with and suck in via gas flow paths 19 through the suction ports 16. The suction by the suction device 18 through the suction ports 16 can prevent the metal plate on the punch press surface 13a from moving relative to the punch press surface 13a.

Description

  The present invention relates to a press molding apparatus and a press molding method for producing a product having linear convex portions, and in particular, a press molding apparatus and method capable of improving the shape transfer accuracy of linear convex portions in press molding of a metal plate. About.

  Some products obtained by press-molding a metal plate (metal thin plate) have linear protrusions. For example, an outer panel for an automobile is formed so as to correspond to a ridge called a “character line” mainly for producing a design effect and an edge of a punch used for press working. A linear convex portion such as a “punch shoulder R portion” which is a bent portion is formed. In recent years, with respect to automotive outer panel, the design effect has been emphasized, and the above-described linear convex portion is required to be transferred from the mold to the metal plate with high accuracy.

  1A to 1D are cross-sectional views for explaining a conventional press molding method as a method for manufacturing a product having linear convex portions. In this press forming method, a flat metal plate is processed by so-called draw forming or stretch forming. In this method, the lower die 1 and the punch 3 are paired with the molds 1 and 3 and the upper die 4 disposed above them is used.

  A columnar hole (die cavity) penetrating in the vertical direction is formed in the lower die 1. The lower die 1 can move up and down with the punch 3 inserted through the hole. A recess corresponding to the punch 3 is formed on the lower surface of the upper die 4. In the upper die 4, the portion other than the concave portion and the lower die 1 are holders (plate pressers) that hold a metal plate (workpiece) W (indicated by a thick broken line in FIGS. 1A to 1D) so as to be slidable. Function as. The lower die 1 is supported via a press spring or a gas cylinder.

FIG. 2 is a perspective view of the punch 3. The press surface (upper surface; hereinafter referred to as “punch press surface”) 3a of the punch 3 has linear protrusions corresponding to the character lines and punch shoulder R portions that are linear protrusions to be formed on the metal plate. Portions 3C and 3S are provided. 1A to 1D show cross sections substantially orthogonal to the linear protrusions 3C and 3S. On the side of the linear convex portions 3C and 3S and on the inner side of the punch press surface 3a, linear concave portions 3R _C and 3R _S are formed substantially parallel to the linear convex portions 3C and 3S, respectively. .

  The upper surface of the concave portion of the upper die 4 is a press surface (hereinafter referred to as “die press surface”) 4a that presses the metal plate W together with the punch press surface 3a. The die press surface 4a faces the punch press surface 3a and has a shape complementary to the punch press surface 3a.

  In the conventional press molding method, first, the punch press surface 3 a is set to substantially the same height with respect to the height position of the holding surface (upper surface) of the lower die 1, the upper die 4 is moved to the lower die 1, and the punch 3. Separate upward. In this state, the metal plate W is placed on the lower die 1 and the punch 3.

  Subsequently, the upper die 4 is lowered. As a result, the holding surface of the upper die 4 (the lower surface of the portion other than the concave portion) contacts the metal plate W, and the metal plate W is slidably held by the lower die 1 and the upper die 4. This state is shown in FIG. 1A.

  As described above, since the lower die 1 is supported via the press spring or the gas cylinder, when the upper die 4 is further lowered, the lower die 1 is lowered together with the upper die 4. Therefore, the punch press surface 3 a is higher than the holding surface of the lower die 1. As a result, the metal plate W protrudes upward on the punch 3 relative to the other parts. In this state, the metal plate W is in contact with the protruding portion on the punch press surface 3a, and there is a gap between the lower portion near the protruding portion and the metal plate W. That is, the metal plate W is not in a shape along the shape of the punch press surface 3a.

When the upper die 4 is further lowered, the protruding portion of the die press surface 4 a comes into contact with the metal plate W. This state is shown in FIG. 1B. When the upper die 4 is further lowered, the linear convex portions 3C and 3S of the punch press surface 3a enter the corresponding concave portions of the die press surface 4a, and the linear concave portions 3R _C and 3R _S of the punch press surface 3a The corresponding convex part of the die press surface 4a enters.

  Accordingly, the metal plate W gradually plastically deforms along the shape of the press surfaces 3a and 4a. At this time, linear bent portions WC and WS are formed on the metal plate W by the linear convex portions 3C and 3S of the punch press surface 3a (see FIG. 1C). In this state, a large tension is generated in the metal plate W, in particular, a portion between the linear convex portion 3C and the linear convex portion 3S.

  As the upper die 4 approaches the punch 3, the tension generated in the metal plate W increases. Since the metal plate W is not fixed to the punch press surface 3a and the die press surface 4a, when the tension reaches a certain magnitude, the linear bent portions WC and WS of the metal plate W With respect to the in-plane direction, it is drawn inward (see FIG. 1D).

  When the upper die 4 is further lowered, the metal plate W is pressed in close contact with the punch press surface 3a and the die press surface 4a. However, the surfaces of the linear bent portions WC and WS already formed on the metal plate W do not become flat or smooth curved surfaces after this pressing. When the external force by the punch 3 and the upper die 4 is removed, the linear bent portions WC and WS appear on the metal plate W.

  On the other hand, in this press, the character lines and the predetermined positions (positions deviated from the linear bent portions WC and WS) by the linear convex portions 3C and 3S of the punch press surface 3a and the corresponding portions of the die press surface 4a, and These character lines and punch shoulder R portions where the punch shoulder R portions are formed remain after the press as well as the linear bent portions WC and WS. Therefore, the metal plate W after pressing has a character line, a punch shoulder R portion, and a linear bent portion formed at a position shifted from these. Such a phenomenon is known as “line shift”.

  As a processing method of a product such as a highly designed outer panel, for example, Patent Document 1 deals with processing of a parting corner portion that appears as a boundary line where a surface intersects in a fender. In this method, the outer peripheral edge side of the workpiece is supported by a trim shelf floated by a gas spring, so that the line deviation of the bending formed mark does not appear in the product. However, this method is a technique for hiding the line deviation of the punch shoulder R portion on the side surface that cannot be seen from the outside of the product, and cannot be applied to a character line positioned on the front side of the product.

  Further, as a method of forming an aluminum alloy plate into an outer panel having high designability, in Patent Document 2, a molding auxiliary convex portion provided on the cushion surface of the die and a molding auxiliary concave portion provided on the surface of the blank holder, There has been proposed a method in which a blank is sandwiched and a central portion of the blank is bent and deformed in advance so as to follow the punch forming surface. However, in this method, since the molding auxiliary concave portion and the convex portion are provided in the mold, the cost and time of mold processing are required. In addition, since the molding auxiliary convex portion and the molding auxiliary concave portion are formed in a portion where a bead (convex portion) is provided in the mold, breakage is likely to occur at the bead portion. Furthermore, there is a high possibility that surface distortion will occur in the blank that has become surplus by pre-bending.

  On the other hand, as a technique for suppressing the displacement of the metal plate with respect to the mold, Patent Document 3 proposes a method of sucking the metal plate with a negative pressure suction device. However, this technology sucks the panel edge with a suction device to prevent misalignment due to the spring back of the panel edge, and the occurrence of line displacement around the character line other than the product edge. It cannot be prevented.

Japanese Patent Laid-Open No. 11-277157 JP 2014-28379 A Japanese Utility Model Publication No. 5-13623

  Therefore, an object of the present invention is to provide a press molding apparatus and a press molding method capable of preventing line deviation due to press working.

  The gist of the present invention is the press molding apparatus (I) below and the press molding method (II) below.

(I) a lower die having a press surface provided with linear protrusions, and a suction port formed at least inside the linear protrusions on the press surface;
An upper mold for pressing the metal plate together with the lower mold; and
A press molding apparatus comprising: a suction device that communicates with the suction port via a gas flow path and sucks from the suction port.

(II) A method of press-molding a metal plate using the press-forming apparatus of (I) above,
Adsorbing the metal plate to the press surface by suction from the suction port of the suction device;
Pressing the metal plate with the lower die and the upper die while the metal plate is adsorbed to the press surface.

  According to the press molding apparatus and the press molding method of the present invention, the metal plate can be brought into a state of being adsorbed on the press surface of the lower mold by the suction device. In this state, the metal plate cannot be easily moved with respect to the lower mold, so the metal plate is pressed against the lower mold by pressing the metal plate with the lower mold and the upper mold. And can be molded while being substantially fixed. Thereby, line shift can be prevented.

FIG. 1A is a cross-sectional view for explaining a conventional press molding method. FIG. 1B is a cross-sectional view for explaining a conventional press molding method. FIG. 1C is a cross-sectional view for explaining a conventional press molding method. FIG. 1D is a cross-sectional view for explaining a conventional press molding method. FIG. 2 is a perspective view of a punch used in a conventional press molding method. FIG. 3 is a cross-sectional view showing a part of a press molding apparatus according to an embodiment of the present invention. FIG. 4 is a perspective view of a punch provided in a press molding apparatus according to an embodiment of the present invention. FIG. 5A is a cross-sectional view for explaining a press molding method according to an embodiment of the present invention. FIG. 5B is a cross-sectional view for explaining a press molding method according to an embodiment of the present invention. FIG. 5C is a cross-sectional view for explaining a press molding method according to an embodiment of the present invention.

  FIG. 3 is a cross-sectional view showing a part of a press molding apparatus according to an embodiment of the present invention. FIG. 4 is a perspective view of a punch provided in the press molding apparatus.

  On the press surface (upper surface; hereinafter referred to as “punch press surface”) 13a of the punch (lower die) 13 is a character line which is a linear convex portion to be formed on the metal plate to be processed and a punch shoulder R portion. Correspondingly, linear convex portions 13C and 13S are provided, respectively. The character line and punch shoulder R portion to be formed may extend linearly or may extend in a curved shape. Therefore, corresponding to this, the linear convex portions 13C and 13S may extend linearly or may extend in a curved shape.

  The character line and punch shoulder R may extend from the edge of the outer panel to the opposite edge. In this case, as shown in FIG. 4, the linear protrusions 13C and 13S are formed on the punch press surface. It extends from the edge of 13a to the opposite edge. Further, the character line and the punch shoulder R portion may not be extended between the edge portions of the outer panel, but gradually become flat and disappear (not a convex portion) in the middle. In this case, the linear protrusions 13C and 13S do not extend between the edges of the punch press surface 13a, but gradually become flat and disappear in the middle.

In this embodiment, the linear convex portions 13C and 13S are provided in the vicinity of the edge portion of the punch press surface 13a. FIG. 3 has a cross section substantially perpendicular to the linear protrusions 13C and 13S. On the side of the linear convex portions 13C and 13S and on the inner side of the punch press surface 13a, linear concave portions 13R _C and 13R _S are formed substantially parallel to the linear convex portions 13C and 13S, respectively. .

A plurality of holes 15 penetrating in the vertical direction are formed in the punch 13. The cross section of each hole 15 is substantially circular. Each hole 15 opens in the punch press surface 13a. Hereinafter, this opening is referred to as “suction port 16”. The diameter of the suction port 16 is, for example, 100 μm to 20 mm. As shown in FIG. 4, the suction port 16 is formed in the linear recesses 13R _C and 13R _S at a high density, and is a region between the linear recess 13R _C and the linear recess 13R _S at a lower density. , and it is formed on the opposite side of the region of linear recesses 13R _C at the side of the linear convex portion 13C. The interval between adjacent suction ports 16 is, for example, 1 mm to 500 mm.

  Each hole 15 is opened to the lower surface of the punch 13, and each opening is connected to a suction device 18 (for example, a vacuum pump) through a pipe 17 and a common main pipe 17 </ b> A. The hole 15, the pipe 17, and the main pipe 17 </ b> A form a gas flow path 19 that communicates the suction port 16 and the suction device 18. Each pipe 17 is provided with a valve 20. By operating the valve 20, it is possible to switch between a state where the gas channel 19 is disconnected from the atmosphere and a state where the gas channel 19 is opened to the atmosphere. When the gas flow path 19 is separated from the atmosphere by the valve 20 and the suction device 18 is operated, suction can be performed from the suction port 16.

  The mold is usually provided with a through-hole for releasing air between the metal plate to be processed and the mold. Such a through hole may be used as the hole 15 of this embodiment.

  5A to 5C are cross-sectional views for explaining a press molding method according to an embodiment of the present invention. In this press forming method, a flat metal plate is processed by so-called draw forming or stretch forming. A press molding apparatus (a press molding apparatus according to an embodiment of the present invention) used in this method includes a lower die 11 and a punch 13 in addition to the punch 13 and the suction device 18 described with reference to FIGS. And an upper die 14 which is paired with the lower die 11 and arranged above them.

  A columnar hole (die cavity) penetrating in the vertical direction is formed in the lower die 11. The lower die 11 can move up and down with the punch 13 inserted through the hole. A recess corresponding to the punch 13 is formed on the lower surface of the upper die 14. The portion other than the concave portion of the upper die 14 and the lower die 11 function as a holder that slidably holds a metal plate W to be processed (shown by a thick broken line in FIGS. 5A to 5C).

  The lower die 11 is supported via a press spring or a gas cylinder. Similarly, the punch 13 is supported via a press spring or a gas cylinder. The upper surface of the concave portion of the upper die 14 is a press surface (hereinafter referred to as “die press surface”) 14a for pressing the metal plate W together with the punch press surface 13a. The die press surface 14a faces the punch press surface 13a and has a shape complementary to the punch press surface 13a.

  In this method, first, the punch press surface 13 a is set at substantially the same height with respect to the height position of the holding surface (upper surface) of the lower die 11, and the upper die 14 is separated above the lower die 11 and the punch 13. Let In this state, the metal plate W is placed on the lower die 11 and the punch 13. The metal plate W can be, for example, a steel plate, a surface-treated steel plate, a stainless steel plate, an aluminum alloy plate, a magnesium alloy plate, or a titanium alloy plate.

  Then, the gas flow path 19 is separated from the atmosphere by the valve 20 and the suction device 18 is operated. Thereby, the metal plate W is adsorbed to the punch press surface 13a. The metal plate W is preferably substantially in close contact with the entire surface of the punch press surface 13a. For this purpose, the metal plate W is easily bent, for example, a thickness of 0.8 mm or less (for example, 0 mm). .65 mm) or high-tensile steel having a tensile strength of 440 MPa or less.

In a state where the metal plate W is adsorbed to the punch press surface 13a, the pressure in the gas flow channel 19, a gauge pressure of, for example, to be the ^{-90 × 10 3 Pa~-10 ×} 10 3 Pa. When the gauge pressure is lower than −10 × 10 ³ Pa, the force for bringing the metal plate W into close contact with the punch press surface 13a can be increased. In order to sufficiently increase the force for bringing the metal plate W into close contact, the gauge pressure is preferably −40 × 10 ³ Pa or less. Moreover, when the gauge pressure is higher than −90 × 10 ³ Pa, the concave shape of the suction port 16 can be hardly transferred to the metal plate W. In order to make the concave shape more difficult to be transferred, the gauge pressure is preferably −70 × 10 ³ Pa or more.

Since the suction ports 16 are formed in the linear recesses 3R _C and 3R _S with a high density, not only the protrusions and substantially flat portions but also the linear recesses 3R _C , 3R on the punch press surface 13a. _The metal plate W can be brought into close contact with _S as well. As a result, the lower surface of the metal plate W is in close contact with almost the entire surface of the punch press surface 13a, and the metal plate W has a shape along the punch press surface 13a.

  By setting the diameter of the suction port 16 to 100 μm or more, the suction force with respect to the metal plate W can be prevented from being greatly reduced, and fine foreign matters such as exfoliation generated by powdering of various members, etc. Thus, the suction port 16 can be prevented from being blocked. In order to sufficiently exhibit such an effect, the diameter of the suction port 16 is preferably 2 mm or more. Moreover, the concave shape of the suction port 16 can be made difficult to be transferred to the metal plate W by setting the diameter of the suction port 16 to 20 mm or less. In order to make the concave shape more difficult to be transferred, the diameter of the suction port 16 is preferably 10 mm or less.

  By setting the interval between the adjacent suction ports 16 to 1 mm or more, it becomes easy to form the adjacent holes 15 so as not to be connected to each other when the holes 15 are formed in the punch. In order to sufficiently exhibit such an effect, the interval between adjacent suction ports 16 is preferably 10 mm or more. Moreover, it becomes possible to attract | suck the air between the punch press surface 13a and the metal plate W in a short time by the space | interval of adjacent suction ports 16 being 500 mm or less. In order to allow air to be sucked in a shorter time, the interval between adjacent suction ports 16 is preferably 100 mm or less.

  Subsequently, the upper die 14 is lowered while the suction by the suction device 18 is continued. As a result, the holding surface of the upper die 14 (the lower surface of the portion other than the recess) is in contact with the metal plate W, and the metal plate W is slidably held by the lower die 1 and the upper die 14. This state is shown in FIG. 5A.

  As described above, since the lower die 11 is supported via a press spring or a gas cylinder, when the upper die 14 is further lowered, the lower die 11 is lowered together with the upper die 14. Therefore, the punch press surface 13 a of the punch 13 is higher than the holding surface of the lower die 11. Along with this, the metal plate W projects upward on the punch 13 with respect to the other parts (see FIG. 5B). The state in which the metal plate W is in close contact with the punch press surface 13a is maintained.

  Then, the upper die 14 is further lowered. Since the metal plate W has a shape along the punch press surface 13a, almost the entire die press surface 14a comes into contact with the metal plate W almost simultaneously (see FIG. 5C). For this reason, the metal plate W does not have a large tension in the in-plane direction as in the case of the conventional press forming method.

  Further, since the metal plate W is attracted to the punch press surface 13a, the metal plate W is not easily displaced with respect to the punch press surface 13a.

  Since the punch 13 is supported via a press spring or a gas cylinder, a cushion load is applied to the metal plate W by the punch 13 and the upper die 14.

  When the metal plate W is pulled out by applying a force T to the side while applying such a cushion load P to the metal plate W without performing suction by the suction device 18, the friction coefficient is T / 2P. When the suction by the suction device 18 is performed, the sliding friction of the metal plate W with respect to the punch press surface 13a becomes larger. Therefore, the apparent friction coefficient defined by T / 2P is the case where the suction by the suction device 18 is not performed. Higher than the coefficient of friction. Hereinafter, the value of the friction coefficient and the value of the apparent friction coefficient are assumed to be those when an oil film is formed on the surface of the metal plate W. Further, the apparent friction coefficient is determined by measurement at a flat surface portion or a gently curved surface portion on the press surface.

  In the present embodiment, suction is performed by a suction device so that the apparent friction coefficient is 0.2 to 1.0. When suction is not performed as in the conventional press molding method, the friction coefficient is less than 0.2. That is, in this embodiment of the present invention, the apparent friction coefficient is increased. Thereby, in the metal plate W, it can fully suppress that the part which contact | connects the linear convex parts 13C and 13S moves. For this reason, a line shift does not occur.

  After the press molding is completed, the valve 20 (see FIG. 3) is operated to open the fluid flow path 19 to the atmosphere. Thereby, the metal plate W can be easily removed from the punch press surface 13a.

  In the above embodiment, the linear convex portions 13C and 13S are provided in the vicinity of the edge of the punch press surface 13a (see FIG. 4), but the linear convex portion is more inward on the punch press surface. It may be provided in the area. Even in this case, line displacement can be prevented by appropriately arranging the suction port on the punch press surface and sucking the metal plate. The suction port is provided at least on the inside of the linear convex portion (on the one side and the other side of the linear convex portion, on the side where a greater tension is applied to the metal plate during pressing) on the punch press surface.

  A punch similar to that shown in FIG. 2 was manufactured, and a hole penetrating the punch was formed. The diameter of the hole, that is, the diameter of the suction port opened on the punch press surface was 50 μm. The arrangement of the suction ports was the same as that shown in FIG. Specifically, the interval between adjacent suction ports was set to 50 mm for the linear concave portion and 250 mm for the substantially flat portion. The suction port of the linear recess was formed mainly for sucking the metal plate and bringing it into close contact with the punch press surface. The suction port of the substantially flat portion was formed mainly for introducing air between the punch press surface and the metal plate when the metal plate was removed from the punch after the press.

  This punch was used as a punch of a press molding apparatus similar to that described in the above embodiment (see FIGS. 3 and 5A to 5C). Each hole formed in the punch was connected to a suction device via a pipe in which a valve was interposed.

  A press molding test was conducted using this press molding apparatus. At this time, a press molding test was performed while sucking at all suction ports, and a press molding test was performed without sucking at some suction ports. The suction port that performs suction by closing the valve of the pipe that communicates with the suction port that does not perform suction (close the flow path to the suction device) and opening the other valve (in communication with the suction device) However, the interval between adjacent ones (hereinafter referred to as “actual suction port interval”) was changed. The actual suction port interval between the linear recesses was any of 50 mm, 100 mm, 500 mm, and 600 mm. Moreover, the press molding test was performed by changing the pressure (gauge pressure) in the gas flow path. As the metal plate to be processed, a plate material made of SPCE and having a thickness of 0.70 mm and a plate material made of SUS304 and having a thickness of 0.60 mm were used. The press was performed by a hydraulic press.

After the press test was completed, the obtained press-molded product (panel) was evaluated, and then the punch was processed to widen the diameter of the hole, and the same test and evaluation as described above were performed. This was repeated to obtain evaluation results of press-formed products when the diameter of the suction port was 50 μm, 5 mm, 10 mm, and 25 mm. Moreover, as a comparative example, press molding was performed without performing suction, and the obtained press-molded product was evaluated.
Table 1 shows test conditions and evaluation results.

Evaluation of the press-formed product was performed as a sensory test by an inspector. The contents of the evaluation results shown in Table 1 are as follows.
○: Almost no line displacement was observed, and almost no transfer of the shape of the suction port was observed.
◇: Almost no line deviation was observed, but the shape of the suction port was transferred.
(Triangle | delta): The grade of line | wire deviation is a grade which is a slight and allowable level, and the shape of the suction opening was not transcribe | transferred.
X: The shape of the suction port was not transferred, but a line shift was clearly recognized.

  When the suction was not performed (comparative example), the line shift was clearly recognized, whereas when the suction was performed (example), the line shift was hardly or even recognized. It was slight and acceptable.

  Further, when suction was performed, a slight line shift was observed when the diameter of the suction port was 50 μm. From this, it can be seen that when the diameter of the suction port is 50 μm, the effect of adsorbing the metal plate to the punch press surface could not be obtained sufficiently. When the diameter of the suction port was 5 mm or 10 mm, no line deviation occurred when the distance between the suction ports and the gauge pressure were appropriate values. When the diameter of the suction port was 25 mm, no line deviation was observed, but the shape of the suction port was transferred to the press-formed product.

13: Punch, 13a: Punch press surface, 13C, 13S: Linear convex part,
13R _C , 13R _S : linear recess, 14: upper die,
14a: die press surface, 16: suction port, 18: suction device,
19: Gas flow path, 20: Valve, W: Metal plate

Claims (8)

A lower die having a press surface provided with linear protrusions, and a suction port formed at least inside the linear protrusions on the press surface;
An upper mold for pressing the metal plate together with the lower mold; and
A press molding apparatus comprising: a suction device that communicates with the suction port via a gas flow path and sucks from the suction port. The press molding apparatus according to claim 1,
The press molding apparatus which is arrange | positioned on the said press surface so that the said suction port can make the said metal plate closely_contact | adhere over the whole surface of the said press surface by the suction from the said suction port by the said suction device. The press molding apparatus according to claim 1 or 2,
A concave portion is formed on the pressing surface,
A press molding apparatus, wherein the suction port is formed in the recess. The press molding apparatus according to any one of claims 1 to 3,
A plurality of the suction ports are formed on the press surface,
The diameter of each suction port is 100 μm to 20 mm,
The press molding apparatus whose space | interval of the said adjacent suction ports is 1 mm-500 mm. A method for press-molding a metal plate using the press-forming apparatus according to any one of claims 1 to 4,
Adsorbing the metal plate to the press surface by suction from the suction port of the suction device;
Pressing the metal plate with the lower die and the upper die while the metal plate is adsorbed to the press surface. The press molding method according to claim 5,
Process, the by aspiration device comprising the step of reducing the pressure of the gas flow path to ^{-90 × 10 3 Pa~-10 ×} 10 3 Pa at gauge pressure, a press molding method for the adsorption. The press molding method according to claim 5 or 6,
The step of pressing includes the step of pressing the metal plate while applying a cushion load P to the metal plate by the lower die and the upper die,
If the apparent friction coefficient is defined as T / 2P when the metal plate to which the cushion load P is applied is pulled out by applying a force T to the side, the adsorbing step has an apparent friction coefficient of 0.2. A press molding method including a step of sucking by the suction device so as to be -1.0. It is the press molding method in any one of Claims 5-7,
The press molding apparatus further includes switching means for switching between a state where the gas flow path is disconnected from the atmosphere and a state where the gas flow path is opened to the atmosphere,
The press molding method further comprising the step of opening the gas flow path to the atmosphere by the switching means after the step of pressing.